[Dammit, Roy, you're not the only PC out here, don't get too self-sacrificing. ...That said, his logic is sound, and she's not going to pretend it isn't just because she's concerned for his safety.]

[Don't think she won't be keeping an eye out for you from up there, though.]

Yes, it would help... The next-nearest one would be over there, that I can see. Cover me while I line up my shot, please?

[She asks as calmly and politely as though she just requested he pass the salt. She's fairly certain he'd watch her back while she was aiming just on principle, but clear communication is rarely a bad thing when you're planning your way around something.]